National approaches to prevent terrorism, extremism, and radicalisation have changed considerably over the last decades. Previous studies mapping these changes have primarily relied on empirical analyses of formal policy and political processes. This case-study of Sweden takes an alternative route, and analyses a dataset of 1405 Swedish newspaper articles (1985-2019) using a new institutional theory and social movement theory framework. Therethrough, the paper is able to provide new insights into the emergence and development of an institutional issue field concerned with the prevention of terrorism, extremism, and radicalisation. More specifically, the paper highlights the unstable, fragmented, dynamic and contested character of the field's development. Frames containing the problems and solutions considered most important during each of the field's five stages are identified, and the subsequent institutional and organisational consequences are discussed. The paper also considers how terror attacks and other extremism-related events impact the institutionalisation and alternation of dominant frames, and identifies the translation and development of an inclusive vocabulary as pivotal to mobilising a broad and diverse set of actors to co-produce preventive efforts.